1. Technical Field
The present invention relates to air pump, and more particularly to an air pump that is capable of engaging an air valve of an article to be inflated in a twist-locking manner.
2. Description of Related Art
The air pump disclosed in U.S. Pat. No. 5,379,796, also issued as Taiwan Patent No. 93676, is one of the inventions made by the inventor of the present invention, and is designed for engaging a tire air valve in a twist-locking manner. The prior-art device uses a cam (22) to press and deform an elastic body (25) that in turn engages firm with the tire air valve. The rotating member (22), i.e. the cam is located by a screw-like locating member (23) screwed thereonto from the exterior of a head housing (21). The fact that leakproof rings (24) have to be provided at both sides of the cam (22) makes the device structurally complicated and leads to time-consuming assembling work. In view of the increase of labor costs, this forms a defect needs to be remedied. In addition, it is hard for an operator through his/her hand feeling to determine whether the cam (22) is correctly located with the cam (22) pressing against the pressing member (27) directly. Moreover, the cam (22) pressing against the pressing member (27) may sometimes undesirably block the through hole (271) of the pressing member (27) and limit the flow.